This invention relates to digital to analog converters, and particularly to optoelectronic digital to analog converters.
Converting a number in one representation to its analog equivalent is a well known process which is very useful in signal processing. Binary to analog conversion is known as DAC (digital to analog converter). Because of electronic parasitics and other undesirable features in analog integrated circuit technology, the electronic DAC's have been limited typically to speeds less than 200 MHz. Although at present generating binary words (or numbers) of appreciable bit length (for example, 12 bits or more) at speeds higher than the current 200MHz limit is a challenge, it is expected that higher speed DAC technology will become useful in the future.
An integrated optic digital to analog converter has been proposed by Carl M. Verber and B. Thomas Smith in APPLIED OPTICS, Vol. 22, No. 23, pages 3677-3678, Dec. 1, 1983. The active element of the proposed converter is an electrooptic integrated optic spatial light modulator which is an extended interdigital electrode structure composed of a number of separately addressable segments.